mc68hc11ea9 Freescale Semiconductor, Inc, mc68hc11ea9 Datasheet - Page 43

• Manufacturer Part Number: mc68hc11ea9
• Description: 8-bit Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

PACTL — Pulse Accumulator Control
Bit 7 — Not Implemented
PAEN — Pulse Accumulator Enable
PAMOD — Pulse Accumulator Mode Select
PEDGE — Pulse Accumulator Input Edge Select
Bit 3 — Not Implemented
I4/O5 — Input Capture 4/Output Compare 5 Select
RTR[1:0] — Real-Time Interrupt Rate Select
7.4 Pulse Accumulator
MC68HC11EA9
MC68HC11EA9TS/D
RESET:
Bits [7:4] can be written at any time. PR[1:0] can only be written once in the first 64 cycles after reset in
normal modes (SMOD = 0). In special modes (SMOD = 1) PR[1:0] can be written any time.
Always reads zero
Refer to 7.4 Pulse Accumulator
Refer to 7.4 Pulse Accumulator
Refer to 7.4 Pulse Accumulator
Always reads zero
Refer to 7.2 Main Timer
M68HC11-family MCUs have an 8-bit counter within the timing system that can be configured for event
counting or for gated time accumulation. The counter (PACNT) can be read or written at any time.
The port A bit 7 I/O pin can be configured to act as a clock in event counting mode and edges on the
pulse accumulator input pin cause the counter (PACNT) to increment. When the pulse accumulator is
configured for time accumulation, an edge on the pulse accumulator input pin enables a free-running
clock (E divided by 64) that drives PACNT in gated time accumulation mode. Refer to Figure 10.
BIT 7
—
0
RTR[1:0]
0 0
0 1
1 0
1 1
PAEN
6
0
Freescale Semiconductor, Inc.
Selected
2
2
2
2
For More Information On This Product,
Rate
13
14
15
16
PAMOD
Table 21 Real-Time Interrupt Rates
E
E
E
E
5
0
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E = 1.0 MHz
16.384 ms
32.768 ms
65.536 ms
8.192 ms
PEDGE
4
0
RTI Rate Selected
—
3
0
E = 2.0 MHz
16.384 ms
32.768 ms
4.096 ms
8.192 ms
I4/O5
2
0
E = 3.0 MHz
10.923 ms
21.845 ms
2.731 ms
5.461 ms
RTR1
1
0
RTR0
BIT 0
0
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